Bio-reducible polycations from ring-opening polymerization as potential gene delivery vehicles.

Synthetic polycations show great potential for the construction of ideal non-viral gene delivery systems. Several cationic polymers were synthesized by the epoxide ring-opening polymerization between diepoxide and various polyamines. Disulfide bonds were introduced to afford the polymers bio-reducibility, while the oxygen-rich structure might enhance the serum tolerance and biocompatibility. The polycations have much lower molecular weights than PEI 25 kDa, but still could well bind and condense DNA into nano-sized particles. DNA could be released from the polyplexes by addition of reductive DTT. Compared to PEI, the polycations have less cytotoxicity possibly due to their lower molecular weights and oxygen-rich structure. More significantly, these materials exhibit excellent serum tolerance than PEI, and up to 6 times higher transfection efficiency than PEI could be obtained in the presence of serum. The transfection mediated by was seldom affected even at a high concentration of serum. Much lower protein adsorption of polycations than PEI was proved by bovine serum albumin adsorption experiments. Flow cytometry also demonstrates their good serum resistance ability.

Et4NI-catalyzed amidation of aldehydes and alcohols with ammonium salts.

An efficient method for the oxidative amidation of benzylic aldehydes or alcohols with ammonium salts has been developed for the synthesis of primary amides using Et4NI as the catalyst and tert-butyl hydroperoxide as the oxidant. This amidation reaction is operationally straightforward and provides primary amides in moderate to good yields under mild conditions.

The benefits of higher LMR for early threatened abortion: A retrospective cohort study.

PROBLEM: To investigate the relation of inflammation-related parameters and pregnancy outcome in women with the early threatened abortion. METHOD OF STUDY: 630 women with early threatened abortion were divided into two groups based on the pregnancy outcome. All of them had the blood routine examination before treating. The differences between two groups were analyzed by the Chi-squared test, Student T test, Mann-Whitney U test, Binary Logistic Regression, Marginal Structural Model and Threshold effect analysis. RESULTS: We found that there is no significant difference in the pregnancy outcome for NLR (OR:0.92, CI95%:0.72, 1.17) and PLR (OR:1.00, CI%:0.99, 1.01). However, a difference had a statistical significance in the pregnancy outcome when LMR less than 2.19 (OR:0.39, CI95%:0.19,0.82). CONCLUSIONS: This study suggested that higher LMR was related to the lower risk of miscarriage in the women with early threatened abortion in a way.

Zn(ii) coordination to cyclen-based polycations for enhanced gene delivery.

1,4,7,10-Tetraazacyclododecane (cyclen) has a unique cyclic structure that endows it with a number of characteristics, including its cationic nature, easy modification and strong coordination ability toward a wide range of cations. Zn2+, which can easily coordinate to cyclen, is an essential metal ion for DNA binding. In this report, Zn(ii)-polycations derived from cyclen were studied as non-viral gene delivery vectors. Polycations were synthesized from diglycidyl ethers and cyclen through ring-opening polymerization, and then Zn(ii)-complexes were obtained by reacting the polycations with Zn(NO3)2·6H2O. UV absorption and circular dichroism spectra revealed that the Zn(ii)-complexes may induce apparent conformational changes of DNA, while polycations could not. Agarose gel retardation assay demonstrated that although the Zn(ii)-polycations exhibited slightly lower DNA binding ability compared to their polycation counterparts, they showed better DNA release, which might favor the gene transfection process. In vitro transfection results revealed that the coordination of Zn(ii) may dramatically increase the transfection efficiency of the polymers. In addition, almost all polycations and their Zn(ii)-complexes exhibited better serum tolerance than polyethylenimine (PEI), especially Zn-cyclen-HD. Flow cytometry and BSA adsorption experiments also demonstrated the good serum tolerance of the Zn(ii)-polycations. Meanwhile, such materials also exhibited acceptable cytotoxicities at transfection dosages. These results may afford us clues for developing novel non-viral gene vectors with high efficiency and biocompatibility.

Low molecular weight PEI-based fluorinated polymers for efficient gene delivery.

Fluorinated biomaterials have been reported to have promising features as non-viral gene carriers. In this study, a series of fluorinated polymeric gene carriers were synthesized via Michael addition from low molecular weight polyethyleneimine (PEI) and fluorobenzoic acids (FBAs)-based linking compounds with different numbers of fluorine atoms. The structure-activity relationship (SAR) of these materials was systematically investigated. SAR studies showed that fluorine could screen the positive charge of these polymers. However, this shielding effect of fluorine would endow fluorinated polymers with good balance between DNA condensation and release. In vitro transfection results suggested that these fluorinated polymers could mediate efficient gene delivery. Flow cytometry and confocal microscopy studies demonstrated that more efficient cell uptake could be achieved by fluorinated materials with more fluorine atoms. Cytotoxicity assays showed that these fluorinated materials exhibited very low cytotoxicity even at high mass ratios. This study demonstrates that FBA-based fluorinated biopolymers have the potential for practical application.

Differences in the Composition of Vaginal Microbiota between Women Exhibiting Spleen-Deficiency Syndrome and Women with Damp-Heat Syndrome, Two of the Most Common Syndromes of Vaginitis in Traditional Chinese Medicine.

Spleen-deficiency syndrome and damp-heat syndrome are the two most common syndromes of vaginitis in traditional Chinese medicine (TCM). Although it is known that the vaginal microbiota is closely associated with vaginitis, present studies have not fully elucidated the relationship between the composition of the vaginal microbiome and type of TCM syndrome because of the limitations in the present reductionist approaches. Samples of vaginal secretions were collected from patients with bacterial vaginitis and healthy subjects with spleen-deficiency syndrome and damp-heat syndrome, in order to analyze the constitution of the vaginal microflora using 16S rRNA sequencing methods that encompass taxonomic units, alpha diversity rarefaction curves, and principal component analyses. This prospective study indicated that there was a statistically significant difference in the composition of the vaginal microbiome between patients with spleen-deficiency syndrome and patients with damp-heat syndrome. Streptococcus was the dominant microbiota in patients with spleen-deficiency syndrome. This can serve as a biomarker for differentiating spleen-deficiency syndrome and damp-heat syndrome. In addition, as indicated by the findings on the samples, patients with bacterial vaginitis of dominant abundance in Pseudomonadaceae might be prone to manifest spleen-deficiency syndrome, while patients with bacterial vaginitis of dominant abundance in Prevotella might be prone to manifest damp-heat syndrome. These present findings can provide a new approach to acquire a scientific understanding of the syndromes of TCM, which in turn would benefit the development of personalized medicine, in terms of ancient medicine and complex biological systems.

Effect of Total Flavones from Cuscuta Chinensis on Anti-Abortion via the MAPK Signaling Pathway.

For centuries, the Chinese herb Cuscuta chinensis has been applied clinically for abortion prevention in traditional Chinese medicine (TCM). Total flavones extracted from Cuscuta chinensis (TFCC) are one of the active components in the herb and also display anti-abortion effect similar to the unprocessed material. However, how TFCC exerts the anti-abortion effect remains largely unknown. In this study, we aim at characterizing the anti-abortion effects of TFCC and its underlying molecular mechanism in vitro and in vivo using human primary decidua cells and a mifepristone-induced abortion model in rat, respectively. The damage to the decidua caused by mifepristone in vivo was reversed by TFCC treatment in a dosage-dependent manner. High dosage of TFCC significantly upregulated the expression of estrogen receptor (ER), progesterone receptor (PR), and prolactin receptor (PRLR) in decidua tissue but downregulated the expression of p-ERK. Furthermore, we detected higher level of p-ERK and p-p38 in primary decidua cells from spontaneous abortion while treatment by TFCC downregulated their expression. Our results suggest TFCC mediates its anti-abortion effect by interfering with MAPK signaling pathway.

Rigid aromatic linking moiety in cationic lipids for enhanced gene transfection efficiency.

Although numerous cationic lipids have been developed as non-viral gene vectors, the structure-activity relationship (SAR) of these materials remains unclear and needs further investigation. In this work, a series of lysine-derived cationic lipids containing linkages with different rigidity were designed and synthesized. SAR studies showed that lipids with rigid aromatic linkage could promote the formation of tight liposomes and enhance DNA condensation, which is essential for the gene delivery process. These lipids could give much higher transfection efficiency than those containing more flexible aliphatic linkage in various cell lines. Moreover, the rigid aromatic linkage also affords the material higher serum tolerance ability. Flow cytometry assay revealed that the target lipids have good cellular uptake, while confocal microscopy observation showed weaker endosome escape than Lipofectamine 2000. To solve such problem and further increase the transfection efficiency, some lysosomotropic reagents were used to improve the endosome escape of lipoplex. As expected, higher transfection efficiency than Lipofectamine 2000 could be obtained via this strategy. Cytotoxicity assay showed that these lipids have lower toxicity in various cell lines than Lipofectamine 2000, suggesting their potential for further application. This work demonstrates that a rigid aromatic linkage might distinctly improve the gene transfection abilities of cationic lipids and affords information to construct safe and efficient gene vector towards practical application.

Aromatic Modification of Low Molecular Weight PEI for Enhanced Gene Delivery.

Low molecular weight polyethylenimine (1800 Da, also referred to as oligoethylenimines, OEI) was modified with amino acids, including two aromatic amino acids (tryptophan, phenylalanine) and an aliphatic amino acid (leucine). The substitution degree of amino acids could be controlled by adjusting the feeding mole ratio of the reactants. Fluorescence spectroscopy and circular dichroism experiments demonstrated that the indole ring of tryptophan may intercalate into the DNA base pairs and contribute to efficient DNA condensation. In vitro gene expression results revealed that the modified OEIs (OEI-AAs) may provide higher transfection efficiency even than high molecular weight polyethylenimine (25 kDa, PEI), especially the aromatic tryptophan substituted OEI. Moreover, OEI-AAs exhibited excellent serum tolerance, and up to 137 times higher transfection efficiency than PEI 25 kDa that was obtained in the presence of serum. The cytotoxicity of OEI-AAs is much lower than PEI 25 kDa. This study may afford a new method for the development of low molecular weight oligomeric non-viral gene vectors with both high efficiency and biocompatibility.

Low Molecular Weight Oligomers with Aromatic Backbone as Efficient Nonviral Gene Vectors.

A series of oligomers were synthesized via ring-opening polymerization. Although the molecular weights of these oligomers are only ∼2.5 kDa, they could efficiently bind and condense DNA into nanoparticles. These oligomers gave comparable transfection efficiency (TE) to PEI 25 kDa, while their TE could even increase with the presence of serum, and up to 65 times higher TE than PEI was obtained. The excellent serum tolerance was also confirmed by TEM, flow cytometry, and BSA adsorption assay. Moreover, structure-activity relationship studies revealed some interesting factors. First, oligomers containing aromatic rings in the backbone showed better DNA binding ability. These materials could bring more DNA cargo into the cells, leading to much better TE. Second, the isomerism of the disubstituted phenyl group on the oligomer backbone has large effect on the transfection. The ortho-disubstituted ones gave at least 1 order of magnitude higher TE than meta- or para-disubstituted oligomers. Gel electrophoresis involving DNase and heparin indicated that the difficulty to release DNA might contribute to the lower TE of the latter. Such clues may help us to design novel nonviral gene vectors with high efficiency and biocompatibility.

Ring-opening polymerization for hyperbranched polycationic gene delivery vectors with excellent serum tolerance.

In order to improve the transfection efficiency (TE) and biocompatibility, we synthesized a series of hyperbranched cationic polymers by ring-opening polymerization between diepoxide and several polyamines. These materials can condense plasmid DNA efficiently into nanoparticles that have much lower cytotoxicity than those derived from bPEI. In vitro transfection experiments showed that polymers prepared from branched or cyclic polyamine (P1 and P5) exhibited TE several times higher than 25KDa bPEI. More significantly, serum seemed to have no negative effect on P1-P5 mediated transfection. On the contrary, the TE of P1 improved, even when the serum concentration reached 70%. Several assays demonstrated the excellent serum tolerance of such polycationic vectors: bovine serum albumin (BSA) adsorption assay revealed considerably lower protein adsorption of P1-P5 than PEI; P1 showed better DNA protection ability from degradation by DNase I than PEI; flow cytometry results suggested that any concentration of serum may not decrease the cellular uptake of P1/DNA polyplex; and confocal laser scanning microscopy also found that serum has little effect on the transfection. By using specific cellular uptake inhibitors, we found that the polyplexes enter the cells mainly via caveolae and microtubule-mediated pathways. We believe that this ring-opening polymerization may be an effective synthetic approach toward gene delivery materials with high biological activity.

TACN-based oligomers with aromatic backbones for efficient nucleic acid delivery.

Cationic oligomers with a rigid aromatic backbone were first applied as non-viral gene delivery vectors. These materials showed better DNA condensation ability than their flexible analogues. In vitro transfection experiments revealed that the materials with more rigid backbone exhibited considerably higher TE and lower cytotoxicity than 25 kDa PEI.